<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .parent {
            width: 300px;
            height: 300px;
            background: url('images/bg.png') no-repeat center center;
            background-size: cover;
            border: 1px solid #333;
            position: relative;
            overflow: hidden;
            margin: 100px auto;
        }
        .cover {
            position: absolute;
            width: 100%;
            height: 100%;
            right:-100%;
            bottom: 0;
            background: rgba(209, 123, 123, .5);
            transition: all 1s;
            transform-origin: left bottom;
           
        }
        .parent:hover .cover{
            transform: rotate(-90deg)
            
        }
    </style>
</head>
<body>
    <div class="parent">
        <div class="cover">
        </div>
    </div>
</body>
</html>